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author | Cyril Bur <cyrilbur@gmail.com> | 2017-11-03 05:41:44 +0300 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-11-06 12:39:28 +0300 |
commit | 9aab24495c5644b25ced0d11816cc3c061bf74fc (patch) | |
tree | 0bfc7bd0fd117ac3c16263aec1f1019ccede50da /arch/powerpc/platforms/powernv/opal-async.c | |
parent | 95e1bc1daaeee4d598b235dc85b64b7a0bcc3060 (diff) | |
download | linux-9aab24495c5644b25ced0d11816cc3c061bf74fc.tar.xz |
powerpc/opal: Add opal_async_wait_response_interruptible() to opal-async
This patch adds an _interruptible version of opal_async_wait_response().
This is useful when a long running OPAL call is performed on behalf of
a userspace thread, for example, the opal_flash_{read,write,erase}
functions performed by the powernv-flash MTD driver.
It is foreseeable that these functions would take upwards of two
minutes causing the wait_event() to block long enough to cause hung
task warnings. Furthermore, wait_event_interruptible() is preferable
as otherwise there is no way for signals to stop the process which is
going to be confusing in userspace.
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/platforms/powernv/opal-async.c')
-rw-r--r-- | arch/powerpc/platforms/powernv/opal-async.c | 84 |
1 files changed, 80 insertions, 4 deletions
diff --git a/arch/powerpc/platforms/powernv/opal-async.c b/arch/powerpc/platforms/powernv/opal-async.c index a8a57310759a..18a355fa15e8 100644 --- a/arch/powerpc/platforms/powernv/opal-async.c +++ b/arch/powerpc/platforms/powernv/opal-async.c @@ -26,6 +26,8 @@ enum opal_async_token_state { ASYNC_TOKEN_UNALLOCATED = 0, ASYNC_TOKEN_ALLOCATED, + ASYNC_TOKEN_DISPATCHED, + ASYNC_TOKEN_ABANDONED, ASYNC_TOKEN_COMPLETED }; @@ -61,8 +63,9 @@ static int __opal_async_get_token(void) /* * Note: If the returned token is used in an opal call and opal returns - * OPAL_ASYNC_COMPLETION you MUST call opal_async_wait_response() before - * calling another other opal_async_* function + * OPAL_ASYNC_COMPLETION you MUST call one of opal_async_wait_response() or + * opal_async_wait_response_interruptible() at least once before calling another + * opal_async_* function */ int opal_async_get_token_interruptible(void) { @@ -98,6 +101,14 @@ static int __opal_async_release_token(int token) opal_async_tokens[token].state = ASYNC_TOKEN_UNALLOCATED; rc = 0; break; + /* + * DISPATCHED and ABANDONED tokens must wait for OPAL to respond. + * Mark a DISPATCHED token as ABANDONED so that the response handling + * code knows no one cares and that it can free it then. + */ + case ASYNC_TOKEN_DISPATCHED: + opal_async_tokens[token].state = ASYNC_TOKEN_ABANDONED; + /* Fall through */ default: rc = 1; } @@ -130,7 +141,11 @@ int opal_async_wait_response(uint64_t token, struct opal_msg *msg) return -EINVAL; } - /* Wakeup the poller before we wait for events to speed things + /* + * There is no need to mark the token as dispatched, wait_event() + * will block until the token completes. + * + * Wakeup the poller before we wait for events to speed things * up on platforms or simulators where the interrupts aren't * functional. */ @@ -143,11 +158,66 @@ int opal_async_wait_response(uint64_t token, struct opal_msg *msg) } EXPORT_SYMBOL_GPL(opal_async_wait_response); +int opal_async_wait_response_interruptible(uint64_t token, struct opal_msg *msg) +{ + unsigned long flags; + int ret; + + if (token >= opal_max_async_tokens) { + pr_err("%s: Invalid token passed\n", __func__); + return -EINVAL; + } + + if (!msg) { + pr_err("%s: Invalid message pointer passed\n", __func__); + return -EINVAL; + } + + /* + * The first time this gets called we mark the token as DISPATCHED + * so that if wait_event_interruptible() returns not zero and the + * caller frees the token, we know not to actually free the token + * until the response comes. + * + * Only change if the token is ALLOCATED - it may have been + * completed even before the caller gets around to calling this + * the first time. + * + * There is also a dirty great comment at the token allocation + * function that if the opal call returns OPAL_ASYNC_COMPLETION to + * the caller then the caller *must* call this or the not + * interruptible version before doing anything else with the + * token. + */ + if (opal_async_tokens[token].state == ASYNC_TOKEN_ALLOCATED) { + spin_lock_irqsave(&opal_async_comp_lock, flags); + if (opal_async_tokens[token].state == ASYNC_TOKEN_ALLOCATED) + opal_async_tokens[token].state = ASYNC_TOKEN_DISPATCHED; + spin_unlock_irqrestore(&opal_async_comp_lock, flags); + } + + /* + * Wakeup the poller before we wait for events to speed things + * up on platforms or simulators where the interrupts aren't + * functional. + */ + opal_wake_poller(); + ret = wait_event_interruptible(opal_async_wait, + opal_async_tokens[token].state == + ASYNC_TOKEN_COMPLETED); + if (!ret) + memcpy(msg, &opal_async_tokens[token].response, sizeof(*msg)); + + return ret; +} +EXPORT_SYMBOL_GPL(opal_async_wait_response_interruptible); + /* Called from interrupt context */ static int opal_async_comp_event(struct notifier_block *nb, unsigned long msg_type, void *msg) { struct opal_msg *comp_msg = msg; + enum opal_async_token_state state; unsigned long flags; uint64_t token; @@ -155,11 +225,17 @@ static int opal_async_comp_event(struct notifier_block *nb, return 0; token = be64_to_cpu(comp_msg->params[0]); - memcpy(&opal_async_tokens[token].response, comp_msg, sizeof(*comp_msg)); spin_lock_irqsave(&opal_async_comp_lock, flags); + state = opal_async_tokens[token].state; opal_async_tokens[token].state = ASYNC_TOKEN_COMPLETED; spin_unlock_irqrestore(&opal_async_comp_lock, flags); + if (state == ASYNC_TOKEN_ABANDONED) { + /* Free the token, no one else will */ + opal_async_release_token(token); + return 0; + } + memcpy(&opal_async_tokens[token].response, comp_msg, sizeof(*comp_msg)); wake_up(&opal_async_wait); return 0; |